vibrate - part-cw/lambdanative GitHub Wiki
(vibrate)
vibrate causes the Android phone or iPhone to vibrate for 400 milliseconds. This procedure does nothing on other platforms. Note that if audio is also being used on an iPhone, the audio subsystem must be shutdown prior to calling vibrate or the vibration will not happen.
Example
Example of stopping the audio subsystem and then performing a vibration.
(audiofile-stop)
(vibrate)